Evaluating a retrospective cohort and publicly available data sets of 72 patients with triple-negative breast cancer revealed that high expression of CCL5 related positively to recruitment of NK cells, reflecting the importance of CCL5 in regulating NK cells in breast cancer.202 In an animal model of triple-negative breast cancer, NK cells activated by cationic nanoparticles effectively inhibited tumor growth by upregulating the expression of CXCR4 and CCR4.203. Here, CXCR4 is linked to neoplasm.